To commemorate the 70th anniversary of the worst fire in Boston history, a few anonymous but history-minded people left flowers this week atop a plaque in a sidewalk in Bay Village. There wasn’t a better way to observe the occasion. Installed in 1993 at the Piedmont Street site of the Cocoanut Grove nightclub, the plaque is Boston’s main memorial to a world-changing disaster and the 492 people who died in it. For pedestrians who know to stop and read it, the plaque has a certain poignancy — according to an inscription, it was crafted by the youngest survivor of the fire — but it doesn’t fully capture the depth of the tragedy or its sweeping implications in subsequent years.

When flames broke out in a lounge just after 10 p.m. on Nov. 28, 1942, the Cocoanut Grove had all the ingredients of a catastrophe. The club was overcrowded; there were too few exits, most of which were obstructed or locked; decorations were made of materials that quickly ignited as the blaze spread around the club. The tragedy offered a window not just into the inadequate fire regulations of the day but also into the politics; word had it that the club’s well-connected owner had just been allowed to open a new section of the Cocoanut Grove without the proper inspections. Over time, the fire had far-reaching effects beyond tougher codes; by many accounts, medical knowledge advanced, as doctors recognized that the toxic gases associated with structure fires could be at least as deadly as flames.

One can’t see all this when looking at the nightclub site, now a fenced-off parking lot, or a sidewalk plaque that is too easily overlooked. (A smaller plaque on a nearby hotel wall is just as nondescript.) The Cocoanut Grove fire is Boston’s equivalent of the Titanic disaster: An epic tragedy whose tremors are still being felt. It warrants a prominent exhibit nearby or a statue or sculpture on part of the nightclub site itself. The 70th anniversary has passed, but perhaps a better memorial will materialize by the 75th.